The Good Samaritans helped pull Shanna McKelvie through the passenger side window of her burning Subaru Outback around 1:30 p.m., said Hopkinton fire Lt. Bill Miller.

Hopkinton Police Sgt. Mike Sutton said McKelvie had left Rte. 495 northbound at Exit 21A and was heading toward downtown when the accident occurred near Cumberland Farms, 91 West Main St.

"She left the roadway and rolled up onto the guardrail and that is what flipped her car over," he said. Her SUV rested sideways against a fence when the bystanders sprang to action with fire extingishers. The Fire Department later put the fire out.

McKelvie, suffering minor injuries, was taken by ambulance to MetroWest Medical Center in Framingham, Miller said. The extent of her injuries was unknown as of Thursday night, Sutton said.

The accident remains under investigation by Hopkinton police.

Jonathan Phelps can be reached at 508-626-4338 or jphelps@wickedlocal.com. Follow him on Twitter @JPhelps_MW.